Our minds must relax: they will rise better and keener after rest. Just as you must not force fertile farmland, as uninterrupted productivity will soon exhaust it, so constant effort will sap our mental vigour, while a short period of rest and relaxation will restore our powers. Unremitting effort leads to a kind of mental dullness and lethargy.

That is never too often repeated, which is never sufficiently learned.

What else is nature but God?

Certain laws have not been written, but they are more fixed than all the written laws.

There is nothing more miserable and foolish than anticipation.

There is no easy way from the earth to the stars.

Pain, scorned by yonder gout-ridden wretch, endured by yonder dyspeptic in the midst of his dainties, borne bravely by the girl in travail. Slight thou art, if I can bear thee, short thou art if I cannot bear thee!